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  1. #1

    Join Date
    Oct 2011
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    Bellingham, WA
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    14

    ELT mount location

    I'm trying to locate my ELT mount in the Sonex I'm building. One place that comes to mind is on the shoulder harness bracket, about 4' behind the cockpit . Advantage is it may need no extra bracing and it's out of the way. Bad thing is it may be too far out of the way. If I need to activate it manually in case the remote switch fails, then this could be a deal breaker. I'm small enough to crawl back on top of the cross braces for annual checks, but I'd not like to do that with a hemo-pneumo post crash. I see most people have mounted them where they are more easily accessible.

    Thanks,
    Dan

  2. #2

    Join Date
    Oct 2011
    Location
    New Hampshire
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    Don't forget that you have to remove the ELT every year to test it.

    Also, I have not looked at the Sonex, but how will putting that mass that far back in the tail affect your weight and balance? You might be surprised by the result when you do the math.

    I assume that you know that an ELT is designed to be mounted aligned with the direction of the expected crash impact forces and that the mounting bracket should implement that design factor. For fixed wing airplane ELT's, many of them need to be aligned fore and aft. The better airplane ELT's and helicopter ELT's are designed to activate in response to crash loads that may come from all axes.

    Best of luck,

    Wes
    N78PS

  3. #3

    Join Date
    Oct 2011
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    Bellingham, WA
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    Thanks, Wes.

    I'd be able to crawl back there annually. It'd be about as hard as crawling under my car to change the oil, only cleaner. Wouldn't want to do it every day, but yearly wouldn't be a problem.

    I think the mass aft of the CG won't be an issue, but that's a good point. Most people mount the ELT a couple feet further forward. I prolly have more weight added forward of the CG than design, so this place may even be better.

    I plan to wear a PLB, or have it mounted someplace that can be accessed in flight. A McMurdo Fast Find 210 (no subscription) is only $200 at some internet outlets, $260 at ACS, but they'll match prices. I hadn't actually considered how having a PLB might influence where I might safely mount the ELT. From the little reading I've done about this, it seems the 121.5 ELT's have a dismal record of activating during a crash and since they aren't sat monitored, don't offer the best coverage, especially in out of the way places where they're really needed. So if I have a PLB, it wouldn't matter much where I mounted the ELT. And if I have survived a crash and need to activate the ELT, I'd certainly be able to activate the PLB, if I hadn't done so on the way down.

    How does this train of logic sound to you?

    Dan

  4. #4

    Join Date
    Oct 2011
    Location
    New Hampshire
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    Everyone's experience is different, so take mine with a grain of salt.

    Relative to the population of aircraft and pilots, crashes are relatively rare and crashes out in the Tulees where no one hears the crunch are even rarer. I spent part of my flying career in antiques and junky skydiving ships and I buy into some wisdom handed down by one of my older peers - "crash near a telephone." And of the many crashes that I know of and that my peers rode through, the vast majority of guys who kept flying the airplane until the crunching noises stopped, climbed out of the remains and walked for help. Modern engines are stunningly reliable if you take care of them and the quality of your average homebuilt is equal to or better then what Cessna/Piper/Mooney is selling. And our airplanes are a lot more rugged than we usually think. So we install and maintain ELT's because we are mandated to, not because we get any utility out of them. I note that the CAP folks spend lots more hours looking for pot fields than looking for missing airplanes these days. But anyway...

    So it sounds like you intend to purchase the minimum ELT to satisfy the regs and carry another device that you believe will be more effective in letting folks know where you are. A reasonable idea with a lot of options. That said, I will offer the suggestion that something like a SPOT, where your track is recorded all of the time will likely get folks to you faster than a manually activated unit. Plus my friends run their SPOT and then go home and pull up their track on their PC, with a map backdrop. They can show their friends and family where they wandered off to. Works for hiking, kayaking, as well as flying. So there is another dimension of utility to the device. Its not just dead weight 99.999% of the time. And if the track logging and the ability to e-mail greetings to your friends have value to you, they wind up being less expensive than a PLB in terms of value. And their built in GPS is as accurate as any other emergency locator.

    I don't know how the consumer PLB's are supported by the emergency services folks. I seem to recall, and I may be wrong or have old info, that you have to register them or folks like the US Coast Guard won't respond to their signal. Yes? No?

    Best of luck,

    Wes
    N78PS

  5. #5

    Join Date
    Oct 2011
    Location
    Bellingham, WA
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    Hmm...so are you saying I should crash near a pot field, Wes?

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    Above are pics of my newly installed ACK E-01. Got it used for $100, complete with tray, straps, cables, remote, and antenna. This is about halfway back in the tailcone. I'll secure the antenna cable, which goes back one more turtle deck former (rib) and up to the top. Remote phone line cable will come forward to the remote which I'll prolly mount on the instrument panel.
    Last edited by messydeer; 12-30-2011 at 08:18 PM.

  6. #6

    Join Date
    Oct 2011
    Location
    Bellingham, WA
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    Thanks for sharing your experience with SPOT. A few months ago I did some preliminary research in PLB's. I won't be buying for a few months more, closer to my plane going up for the first time, and will do more digging before I buy. I didn't like the idea of paying a yearly subscription to a device. Lots of them had this mandatory fee and I think SPOT was one of them. It may turn out that it's a better deal than a no frills, subscription free device like the McMurdo. I mentioned it cuz it was the cheapest without a subscription.

    Below is a pic from the cockpit, showing the ELT ~3.5' back. For service, I'd slap a plank down the middle and shimmy back to the unit.

    Attachment 1351

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